The Traveller is a strange, medium-sized (6'6)  humanoid merchant who seems to show up when our adventurers need him most, with the items they require. Always travelling in his cart with his animal companion, Midas, the Traveller mysteriously seems to have the ability to go anywhere at all, despite having no horse to pull him. Tales of the Traveller spread through those who are lucky (or unlucky) enough to encounter him. Does he have legs? No one has seem him leave the cart before. How does he acquire all these magical objects, and how do they all fit in that small cart? What species is he exactly? Most of his face is always hidden. Where is he from? His accent and tone of voice can change several times during a conversation.

He normally only goes by the name 'the Traveller', but if you pry he will give an alias. They are usually on the fly based on items, but sometimes they can be rather humourous. Some examples are Maverick Flint, Benjamin Dover (usually only used in brothels), Mike Superbacker, Earl E. Byrd, Felix Cited.

Despite how suspicious all this is and despite his terrifying appearance, the Traveller isn't an inherently evil being. He is a soldier of balanced chaos - Appearing where his heart tells him he is needed to either create or remedy chaos and achieve proper balance in the world. Due to this, his items may be extremely helpful, or potentially cursed. It all depends on what the world needs to remain in balance. Of course, he sometimes also lets his emotions get the better of him, so he may be convinced to be helpful even when he shouldn't be, or might be convinced to curse a player that is being unnecessarily cruel. 

When met with hostility, the Traveller still prefers not to fight. Even if one threatens him or steals his items, he will likely not fight them. If forced to fight (either fighting a player character or aiding in battle if he's in the wrong place at the wrong time), it won't take him long to try and find an exit strategy. 
He doesn't truly fear anyone except for his brother, another soldier of chaotic balance who has decided that creating trouble is more fun than keeping things equal. This is why he is constantly moving - To ensure that his brother is never to find him. But he's not one to mention much of his family life, and is more likely to dodge any questions.

Note: Midas's stat block is currently under construction, so it may be best to have him flee if combat occurs. His most common form is a black Oriental cat but in all forms, he has a general black theme (for fur, feathers etc). His eyes are grey, left eye with a glowing white pupil and right eye with a grey, nearly unseen pupil. On the left side of his face over his eye is a swirling grey pattern with lighter grey specks, that resembles a galaxy. He would be very unlikely to transform into his humanoid form, but in his human form he has tan skin, the same eyes and a birth mark instead of the pattern on the face. He has longer raven hair and a strong, muscular build, and is 6'4. 
If you do want to include him in combat, you may use stats for a LVL 10 Druid, He is able to use Wild Shape at will, and for an unlimited amount of time, but only to transform into his 'favorite forms' (a cat, panther, owl, humanoid or horse). 
Midas can also use Wild Shape to transform into forms other than his favorite form. This feature can only be used twice until the uses are regained through a short or long rest. These forms can only be used for 5 hours, at which point, he will revert into his cat form. If rendered unconscious or killed, Midas will revert to his cat form.
Midas can also take a point of exhaustion to transform into a non-favorite form after his two uses have been spent. Of course, this gives him the negative effects of exhaustion, so can only be done 5 times without penalty of death.

The Traveller's cart (15ft x10ft, 8ft tall) is a dimensional tool used to transport the Traveller across dimensions. It can appear in any room that is at least slightly larger than the size of the wagon, with no need for a horse to transport it. The cart has a small window in which the Traveller can sell his items from, and behind him appears to be nothing but a black void. 

The cart is protected by several abilities to prevent robbery.

Illusionary Room. Entering the cart from the back or the window without ill intent will result in the creature entering what appears to be a regular travelling wagon, with two bedrolls on the floor of the cart, and various food and low value items scattered around. There is hay on the ground, and it smells vaguely like apple pie.

Cursed sigil. All items on display have a hidden, cursed sigil that must be dispelled by The Traveller upon purchase of the item. If the item goes out of a certain range of the shop, after 3 hours, the sigil activates. The item seemingly implodes before exploding outward, creating a loud blast of magical fire. Each creature in a 20-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 8d6 fire damage on a failed save, or half as much damage on a successful one. The fire spreads around corners. It ignites flammable objects in the area that aren’t being worn or carried. The item is teleported safely back to The Traveller's cart. 
The sigil can be found with spells like detect magic or with a high perception roll (up to the DM's discretion). If found, it can also be dispelled by magic such as dispel magic.

Trapped wagon. Entering the cart from the back or the window with ill intent will activate the magic trap. If all enter at once, only one effect will take place. If entering separately, the player characters may all enter different 'interiors' and have to deal with individual effects, or they may enter the same interior as the first intruder (up to the DM's discretion). Roll a D10, or choose from the effects:

1. This effect can only affect one of the characters in the party. If rolled by a second character, choose another effect. When entering, the player instead teleports into a pocket dimension (as per the banishment spell) and replaces them with a doppelganger that looks exactly like them. Additionally, the doppleganger appears to take damage from illusionary flames. When this happens, the DM should take the player whose character was replaced away from the group, explain what has happened, and let them play the doppelganger. The DM should give the player some basic information to inform their roleplaying, such as the doppelganger’s motivations. This effect lasts until the doppelganger dies, at which point the character is teleported to where the doppelganger perishes, taking the place of its body. As a countermeasure, a character who is suspicious of the doppelganger can make a Wisdom (Insight) check contested by the doppelganger’s Charisma (Deception) check. If the character wins, he notices small imperfections with the doppelganger’s disguise or acting, cluing him in that it is not actually the character. 
2. A pair of large disembodied hands float in front of and block a passage. To get past, the characters must shake hands with them. If the hands are attacked or someone tries to push them out of the way, the hands slap the offenders. They have a +8 to hit and deal 4d10 bludgeoning damage.
3. The intruder becomes poisoned for 1d4 hours.
4. A magical floating scythe makes a melee attack against the intruder at a +6 to hit. On a successful hit, it does 1d8+2 slashing damage.
5. The interior of the wagon is replaced with a dark room. Upon entering, the intruder falls into a spiked pit. A creature falling into the pit takes 11 (2d10) piercing damage from the spikes and must make a DC 13 constitution saving throw. On a failed save, they take 4d10 poison damage and gain the poisoned condition. On a successful save, they take half the amount of damage and are not poisoned.
6. When the intruder enters the wagon, all entrances are sealed by arcane magic, and no one (except for the Traveller and Midas) can enter or leave unless the magic is dispelled, or until 5 hours have passed. Here's hoping the intruder didn't drink water before coming in.
7. Rocks fall on top of the intruder. They are restrained and take 4d6 bludgeoning damage.
8. The interior of the wagon is replaced by a room filled with rotting, diseased corpses. If the corpses are touched during an investigation, the player must make a DC16 constitution save. Upon failing the save, the player is inflicted with [Tooltip Not Found]. On a successful save, they have a chance to find loot based on their investigation roll (up to DM's discretion). 
9. The players steps on/lands in a bear trap in a darkened room and take 1d4 piercing damage and and are stuck in place. While the player is in the trap, they have a movement speed of 0. They must make a DC 13 strength check in order to break free. Anyone entering must also make a DC 10 perception check. Upon success, it will reveal that the room is filled with only more active bear traps. If the perception check is failed, the player gets stuck in another bear trap when they try to move.
10. The interior of the wagon is replaced with a room filled with 6 ornate chests. All are unlocked. All are mimics.

In reality, the cart's true purpose is a dimensional door to the Traveller's warehouse, stocked with various goods and treasures the Traveller has accumulated throughout his own adventures and trading. This warehouse, along with the Traveller's home, reside in their own pocket dimension. Only the Traveller and Midas are able to travel freely between the wagon and this dimension.